Alberta Premier Alison Redford says she has confidence in her sister Lynn Redford, but says she needs to let the investigation into whether illegal donations were made to the Progressive Conservative party proceed independently.

"I cannot expect that Albertans would want me as the premier of the province to stand here at a podium and start defending my sister or for that matter, criticizing my sister," Redford said in Red Deer on Wednesday.

"That's why we have systems in place ... in terms of determining what happened, and what the outcome of that should be, we have to respect the processes and that's what I'm going to do."

As CBC News first reported on Monday, expense reports revealed that while she was an executive at the Calgary Health Region, Lynn Redford claimed all or part of the costs of attending the PC party's annual general meeting in Edmonton and several fundraisers, including premier's dinners and a golf tournament fundraiser for a Tory MLA.

Alberta law prohibits public institutions, such as health regions, from making donations to political parties.

Redford declined to comment directly about her sister's situation, adding that it doesn't mean that she lacks confidence in her.

"Politics is different in this province right now and it's been for some time. I care an awful lot about my sister, and you can imagine if it was your sister that there would probably be some pretty difficult moments," Redford said.

"One way or the other, it doesn't matter because what we're going to do is follow the processes that we should all have confidence in as Albertans to get to the bottom of this matter."

The revelations prompted the Wildrose Party to file a complaint with the chief electoral officer asking him to conduct an investigation.

Wildrose Leader Danielle Smith also sent a letter to John Vertes, the retired judge heading the Health Services Preferential Access Inquiry, asking him to call Lynn Redford as a witness.

Redford said that it was inappropriate for Smith to make that request.

"I was shocked that a political leader would then send a letter to the chair of an independent judicial inquiry, telling them what to do," she said. "It's inappropriate and I think that it doesn't respect the system."

"If we had done that, someone would be standing out on the steps of the legislature saying that we have politically interfered with an independent judicial process."